Two-way communication radios allowing for multiple channel transmission and reception of messages have long been known in the art. As standard equipment such radios incorporate a hand-held microphone having a "press-to-talk" transmission switch that must be manually activated to transmit a message. Such radios also typically include a scanning feature. In the scan mode of operation; the radio scans through all or a programmed group of the multiple channels so as to allow the monitoring of communications taking place. Two-way radios of this type are presently manufactured by a number of companies under brand names including: Motorola, General Electric, Uniden, Kenwood, Regency, Wilson and Bearcat.
A primary market for the sale of two-way communication radios is law enforcement and public safety agencies. Specifically, these agencies install a two-way communications radio in each of their vehicles so that an officer or official in the vehicle may benefit from two-way communication with a dispatcher at a central information processing location.
Many times the operator of the vehicle must communicate with the dispatcher while the vehicle is in motion. Unfortunately, the manipulation necessary to communicate utilizing the standard equipment, hand-held microphone with the manually operated transmission switch may cause the operator to compromise vehicle control. This is particularly true in high speed pursuit situations when the operator must either remove his eyes from the road to visually locate the microphone or blindly feel for the microphone. In either event, the operator must also remove a hand from the steering wheel to grasp the microphone thereby surrendering some control and adversely affecting the directional stability of the vehicle.
Recognizing this shortcoming, several attempts have been made in the past to provide for hands-free operation of the two-way radio in a vehicle. Specifically, the goal of these prior art devices has been to allow the operator to transmit a message over the two-way radio without removing his hands from the steering wheel or his eyes from the road. Examples of such prior art systems are disclosed in U.S. Pat. Nos. 3,906,472 to Guadara et al. and 4,151,468 to Kerr.
In the Guadara et al. patent the radio communication system incorporates a transmitter, a normal press-to-talk microphone, and a hands-free microphone. Foot operated switches allow control of the hands-free microphone.
In Kerr, a standard press-to-talk microphone is positioned in a holder adjacent to the mouth of the driver and an actuating mechanism for the microphone is controlled by a foot pedal.
While each of these approaches do allow for the transmission of messages over the two-way radio without diverting the eyes of the vehicle operator from the road or the hands of the vehicle operator from the steering wheel, these approaches do not allow multiple channel two-way radios to be operated in the "scan mode".
As previously discussed, when in the scan mode, the radio scans through the multiple channels for communication signals. Due to a need to remain informed of events requiring their attention, police officers on patrol in their vehicles regularly monitor communications over a number of channels using this scan feature. Hence, it should be appreciated that the scan feature is an important radio function and any hands-free transmission capability must be compatible with the use of the scan function.
The scan mode functions when that mode is selected for operation and the standard microphone is in its resting or "hooked" position on the side of the radio. Only when the microphone is lifted or "unhooked" from the radio does the radio switch to a primary communication channel for transmission of a message to the dispatcher.
At present, no prior art system for the hands-free operation of a two-way radio known to the inventors will allow the operator to take advantage of the important scanning feature built into present day radios. A need is, therefore, identified for an improved system allowing both hands-free message transmission and scan mode function so that an operator may take the fullest advantage of the available operation features of the radio.